This invention relates to an infusion bag, that is, a liquid-pervious bag containing a substance, such as tea leaves for preparing beverages. The infusion bag is of the type which has two face-to-face arranged panels of liquid-pervious filter material sealed, bonded or otherwise continuously connected to one another to form a bottom as well as front and rear side walls and has an unsealed portion forming an opening situated opposite the bottom. Such a construction is disclosed, for example, in European patent document 0 020 598 B1.
In addition to egg-shaped, perforated, usually metal containers for tea leaves to be submerged in teapots for the preparation of tea, closed bags made of filter material have been known which contain a predetermined quantity of tea leaves. Also, filter inserts (funnel-shaped members) are known which are clamped into a holder and may then receive tea leaves.
The infusion bag disclosed in EP 0 020 598 B1 is formed of a bag made of a filter material and having an opening. The bag is subdivided into a funnel portion and a receiving portion. The opening of the bag is provided at the upper end of the funnel portion, that is, at that end which is oriented away from the receiving portion. Between the two portions a passage is provided whose inner width is significantly less than the inner width of the receiving portion. It is a disadvantage of this construction that the introduction of tea leaves is difficult. The opening of the initially flat bag cannot be satisfactorily brought to the size necessary for an easy insertion of the tea leaves. It is a further disadvantage of this prior art construction that the passage between the funnel portion and the receiving portion is too narrow to permit a free and simple throughflow of the tea leaves.